The present invention relates to an exhaust gas cleaning device for eliminating particulates such as carbon particles in exhaust gases of an internal combustion engine, particularly to an exhaust gas cleaning device provided with a particulates collecting member and heated air supplying means for burning the particulates collected by the particulates collecting member, in the exhaust gas passage.
The present invention more particularly relates to an exhaust gas cleaning device provided with two particulates collecting members which alternately collect particulates and having such a cleaning system that the particulates collected by one inactive particulates collecting member are burnt by the heated air supplying means while the products of combustion are recycled into the other active particulates collecting member.
FIG. 1 shows one example of such a conventional exhaust gas cleaning device as described above, which is disclosed in U.S. Pat. No. 4,167,852.
A housing 4 is provided with inlet ports 2 and an outlet port 3. The housing 4 is connected to an internal combustion engine 1 through the inlet ports 2. Exhaust gases discharged from the internal combustion engine 1 flow into the housing 4 through the inlet ports 2 and are discharged from the housing 4 through the outlet port 3. Within the housing 4, two independent exhaust gas flowing passages 51 and 52 are formed in parallel with each other. And in one end portion of the flowing passages 51 and 52, on the side of the inlet ports 2, an exhaust gas inlet chamber 6 is formed while in the other end portion of the flowing passages 51 and 52, on the side of the outlet port 3, an exhaust gas outlet chamber 7 is formed.
In each of the flowing passages 51 and 52, heat resistant filter members 81 and 82 which operate as particulates collecting members, are provided respectively.
And in the exhaust gas inlet chamber 6, a diverter valve means 9 for directing the flow of exhaust gases to either collecting member 81 or 82 is provided. Therefore, the exhaust gases containing particulates such as carbon particles discharged from the internal combustion engine 1 flow into the collecting member 81 as shown by hatched arrows, for example.
The conventional exhaust gas cleaning device is further provided with a nozzle 101 for injecting an air-fuel mixture and an ignition means 102 between each of the particulates collecting members 81 and 82 and the valve means 9.
The nozzle 101 and the ignition means 102 operate as the heated air supplying means for heating and burning the particulates collected by the inactive particulates collecting member 82.
A flow redirecting valve 11 is provided in the exhaust gas outlet chamber 7 for redirecting the combustion products collected in either one of the particulates collecting members 81 and 82 into the exhaust gas flowing passage communicated with the other particulates collecting member.
A recycling passage 12 is provided between the exhaust gas outlet chamber 7 and the exhaust gas inlet chamber 6 for recycling the flow of exhaust gases containing the combustion products which is directed by the flow redirecting valve 11 into the exhaust gas inlet chamber 6, to be joined into the flow of exhaust gases which flow into the active particulates collecting member. The heated air supplied by the heated air supplying means 101 and 102, is supplied into the inactive collecting member 82 as shown by a dotted line.
Then, the heated air containing the combustion products flows into the exhaust gas inlet chamber 6 through the recycling passage 12 and mixes with the incoming exhaust gases from the internal combustion engine 1. The combustion products recycled from the inactive collecting member 82 and the particulates in the exhaust gases are eliminated while passing the active collecting member 81 and the cleaned exhaust gases pass out from the outlet port 3 as shown by a white arrow.
When the amount of the collected particulates in the active collecting member reaches such a level as to restrict the flow of exhaust gases, a manual or automatic control device (not shown) changes the positions of the diverter valve means 9 and the flow redirecting valve 11 as shown respectively by imaginary lines so that the particulates collecting operation and particulates burning operation of the particulates collecting members are alternated with each other.
By burning the collected particulates collected by each of the particulates collecting members, the particulates collecting member is prevented from being clogged by the particulates.
And the combustion products which are formed in the inactive collecting member are cleaned by supplying the combustion products into the other active collecting member.
The conventional exhaust gas cleaning device as described above requires the diverter valve means 9, the flow redirecting means 11, and the recycling passage, and furthermore requires such a control device as to operate the diverter valve means 9 and the flow redirecting means 11 in combination with each other in order to recycle the gas containing the combustion products.
Therefore, the conventional exhaust gas cleaning device becomes large and heavy so that a large mounting space is required.
Accordingly, one object of the present invention is to provide a small sized and light weighted exhaust gas cleaning device having a simple construction, which overcomes the defects of the conventional exhaust gas cleaning device as described above.